Semiconductor devices are used in a variety of electronic applications, such as personal computers, cell phones, digital cameras, and other electronic equipment. Semiconductor devices are typically fabricated by sequentially depositing insulating or dielectric layers, conductive layers, and semiconductor layers of materials over a semiconductor substrate, and patterning the various material layers using lithography to form an integrated circuit (IC) and elements thereon. ICs in the newer generations have more complex circuits than ICs in the previous generations as technologies advance. However, for these advances to be realized, similar developments in IC processing and manufacturing are needed.
During the manufacturing of semiconductor devices, various processing steps are used to fabricate integrated circuits on a semiconductor wafer. One of the most difficult factors in the continuing evolution toward smaller device sizes and higher circuit density is to consistently form circuits with smaller critical dimensions within predetermined error windows. For example, semiconductor feature sizes are frequently subject to optical or electrical metrology inspections following photolithographic patterning and etching to ensure that critical dimensions are within acceptable limits.
Although existing methods and devices for performing the processing steps have been generally adequate for their intended purposes, they have not been entirely satisfactory in all respects. Consequently, it would be desirable to provide a solution for process control in semiconductor manufacturing operations.